The present invention relates to adjustable mounting means for an optical element, and more particularly to mounting means capable of adjusting the optical element orthogonally about axes passing through the geometric center thereof without cross-coupling.
In a variety of applications, such as laser, image projection and photoelectric systems, it is frequently desirable that optical elements and components be mounted in the system by means that are kinematic, easily adjustable to a desired position, easily lockable in the desired position, mechanically and thermally stable, free of backlash in the adjusting mechanism, and capable of fine incremental changes orthogonally about axes passing through the geometric center thereof without cross-coupling.
To obtain orthogonal adjustability free from cross-coupling, resort is typically had to gimbal mounts in which the optical element is carried by an inner gimbal connected by two bearings along a first axis to an outer gimbal which is in turn connected to a stationary base by means of two more bearings along a second axis perpendicular to the first axis. However, the known gimbal mounts have not proven to be entirely satisfactory for a variety of reasons. The gimbal structure is relatively complex and typically requires the use of at least four small individual pivots or bearings which can develop play or looseness, thereby detracting from the stability of the mount. Typical gimbal construction involves the use of asymmetrically disposed dissimilar materials, thus making the mount more sensitive to thermal effects and reducing thermal stability. Due to the nature of the gimbal mount only one of the adjusting means can be mounted on a fixed and rigid support (namely, the base); the second adjusting member be mounted on the outer gimbal which is a movable part and therefore subject to positional disturbance from hand contact while manual adjustments are being made using the second adjusting member. Finally, most gimbal mounts rely on spring means to maintain the desired positional settings once obtained through adjustment, and cannot be locked to secure the achieved positional setting against subsequent variations due to shock or vibration.
Accordingly, it is an object of the present invention to provide an optical mount enabling independent orthogonal adjustment of the angular position of an optical element without cross-coupling.
It is another object to provide such a mount which does not require the use of any small pivots or bearings.
It is also an object to provide such a mount characterized by a high level of thermal stability.
It is a further object to provide such a mount in which all adjusting means are supported in a rigid fixed support for ease of adjustment and maximum stability during adjustment.
Another object is to provide such a mount which may be locked in its desired setting.
A final object is to provide such a mount which is characterized by a simple, sturdy and inexpensive construction.